Bottles or other types of containers can be used for liquids, for example for beverages. These bottles can be produced from a transparent or translucent material, for example glass, or from a translucent plastic material, e.g. PET. While empty, and preferably after having been cleaned, the bottles are moved passed an inspection device.
To permit inspection, an illuminating device is located, for example, below the bottle to be inspected, and a first camera is located opposite the illuminating device. The illuminating device illuminates the bottle so that the camera can check whether there are any foreign substances in the bottle or whether the bottle has sustained damage. Examples of foreign substances include, for example, adhesive films (TESA®) or other unwanted objects and contaminants.
To this end, the camera is aligned onto a bottom region of the bottle such that only the bottom region, or the bottle's bottom, is inspected from the inside. Using a second inspection device, it is possible to inspect an inside wall region of the bottle for unwanted objects, contaminants or damage. If the two inspection devices detect unwanted objects in the bottle, or that the bottle has contaminants or damage in or on the inspected region, the bottle is rejected. Corresponding means are provided for this purpose to process the image acquired by the camera or to compare the image acquired by the camera with another image, and to then transmit a corresponding signal to suitable sorting devices.
Inspecting the interior of the bottle for liquid residue or the like is also known, it being possible to provide a camera that uses infrared light for this purpose. The inspection devices inspect the relevant region (i.e. the bottom and/or inside wall of the bottle), but only once each time. This means that errors can occur and only unreliable assertions concerning the presence of unwanted objects, contaminants in or damage sustained by the inspected region can be made.
In addition, the use of a plurality of inspection devices following one after the other is disadvantageous because a bottle then has to run through a plurality of inspection devices in order to have all of its defined inside regions inspected.